Shining light on the electronic structure and relaxation dynamics of the isolated oxyluciferin anion.
Shining light on the electronic structure and relaxation dynamics of the isolated oxyluciferin anion.
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DOI：
10.1039/d0cp03276j
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
A. Patel;Alice Henley;M. Parkes;Mariana Assmann;G. Worth;James C. Anderson;H. Fielding
中科院分区：
文献类型：
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作者：
A. Patel;Alice Henley;M. Parkes;Mariana Assmann;G. Worth;James C. Anderson;H. Fielding
萤火虫生物发光在生物化学与生物医学成像中应用广泛；然而，我们对于发光的氧化荧光素的电子结构和弛豫过程的基本认识仍很初步。在此，我们运用光电子能谱和量子化学计算来研究一系列氧化荧光素阴离子模型的电子结构与弛豫情况。我们发现，改变去质子化位点，对较高电子激发态光激发后的弛豫途径有显著影响。研究发现，氧化荧光素阴离子的酮式会发生系间窜越至荧光S1态，而我们找到的证据表明，烯醇式和烯醇盐式可能经由荧光S1态，发生系间窜越至偶极束缚态。部分解析出的振动结构表明，面外扭转运动参与了向偶极束缚态的系间窜越，这突出了微环境在控制酶中电子弛豫途径方面所起的电子与结构双重作用。
Firefly bioluminescence is exploited widely in imaging in the biochemical and biomedical sciences; however, our fundamental understanding of the electronic structure and relaxation processes of the oxyluciferin that emits the light is still rudimentary. Here, we employ photoelectron spectroscopy and quantum chemistry calculations to investigate the electronic structure and relaxation of a series of model oxyluciferin anions. We find that changing the deprotonation site has a dramatic influence on the relaxation pathway following photoexcitation of higher lying electronically excited states. The keto form of the oxyluciferin anion is found to undergo internal conversion to the fluorescent S1 state, whereas we find evidence to suggest that the enol and enolate forms undergo internal conversion to a dipole bound state, possibly via the fluorescent S1 state. Partially resolved vibrational structure points towards the involvement of out-of-plane torsional motions in internal conversion to the dipole bound state, emphasising the combined electronic and structural role that the microenvironment plays in controlling the electronic relaxation pathway in the enzyme.